Sampling Methods

Probability sampling (random sampling)

ο It is a selection process that ensures each participant the same probability of being selected.ο Random sampling is the best method for ensuring that a sample is representative of the larger population.ο Random sampling can be:

simple random sampling

stratified random sampling, and

cluster sampling.

Nonprobability sampling

ο It is the selection process in which the probability that any one individual or subject selected is not equal to the probability that another individual or subject may be chosen.ο The probability of inclusion and the degree to which the sample represents the population are unknown.ο The major problem with nonprobability sampling is that sampling bias can occur.ο Nonprobability sampling can be:

Difference Between "Population" and "Sample"

While "population" is about the generality of the universe or groups of people, "sample" refers to a fraction of persons from the population.

It is from the sample that data is collected in the course of a study, and because that sample is representative of the population, the results can be generalized to the population in a scientific study.